Fig. 3

T-MSCs-Exo can cross the BBB to reach the SN and alleviate the degeneration of DA neurons in PD mice. a We injected PKH26-labeled T-MSCs-Exo into mice via the tail vein, and subjected them to cardiac perfusion for brain extraction at 0, 2, 6, 8, 10, 12 and 48 h. Next, we prepared frozen sections and detected the uptake of PKH26-labeled T-MSCs-Exo in the DA neurons of the midbrain at each time point using immunofluorescence. The number of mice at each time point was three. Scale bars, upper, 20 µm; lower, 5 µm. b Schematic of in vivo experimental protocol. c Open field experiment. d–f Representative images and quantification of IHC of TH-positive neurons in the striatum and SNpc of the control, T-MSCs-Exo, MPTP, and MPTP + T-MSCs-Exo groups (n = 3 per group). Scale bars, 2.5 mm for images in striatum; 625, 200, and 100 µm for the series of images in SNpc. g, h Immunofluorescence staining and quantification of TH expression in MPTP-induced PD mice after treatment with T-MSCs-Exo (n = 3 per group). Scale bars, upper, 100 µm; lower, 50 µm. i, j Western blotting analysis showed the TH expression levels in the SN of the control, T-MSCs-Exo, MPTP, and MPTP + T-MSCs-Exo groups (n = 3 per group). The results are shown as mean ± SD. One-way ANOVA was used to analyze the data. *p < 0.05, **p < 0.01